Work table height adjusting mechanism for blindstitch sewing machines



Jl'y 21, 1959 F. PARRY 2,895,442 woRx TABLE: HEIGHT ADJusTING MECHANISMFOR l BLINDsTIIcH SEWING MACHINES Filed Nov'. 14, 1955 2 Sheets-,Sheet 1.//vvE/vron, .Fran/r Parry By wia/wn July `21, 1959 Y F. PARRY 2,895,442WORK TABLE HHIGH'I` ADJUSTING MECHANISM FORv 4 BLINDSTITCH SEWINGMACHINES Filed Nov. 14, 1955 2 Sheets-Sheet 2 lllllllllllluw I y AWE/vm? Y I l F ran/r Parry w/r/vfss By T ORA/E Y Unid WORK TABLE HEIGHTADJUSTING MECHANISM FR BLINDSTITCH SEWlNG MACHINES Frank Parry,rlrurnlnrll, Conn., assigner to The Singer Manufacturing Company,Elizabeth, NJ., a corporation of New Jersey Application November 14,1955, Serial No. 546,55e

3 Claims. (012112-260) This invention relates to sewinggmachnes and,more particularly, to mechanism for controlling the elevation of thework supporting table of a blindstitch sewing machine.

It is an object of this invention to provide a positive stop `definingthe upper limit of work table movement in a `blindstitch machine.

Another object of `this invention -is to provide a work table elevationcontrolling device for a blindstitch sewing machine with which either awide range of adjustment or a iine micrometer adjustment of work tableelevation may be made with equal facility.

Withthe above and other objects and advantages in view, as willhereinafter appear, this invention comprises the devices, combinations,and arrangements of parts hereinafter described and illustrated in theaccompanying drawings of a preferred embodiment thereof in which:

Fig. l represents a vertical sectional View of a machine constructed inaccordance with my invention taken longitudinally of the base andthrough the standard and work table and having portions of the ridgeformer actuating mechanism broken away to expose the work table heightadjusting mechanism.

Fig. 2 is an enlarged view of a portion of the sewing machine of Fig. 1,showing the base portion of the machine frame taken in cross-sectionsubstantially along line 2-2 of Fig. l and having parts of the machineframe broken away to expose the work table height adjusting mechanism.

Fig. 3 represents a cross sectional view taken substantially along line3-3 of Fig. 2.

Referring to the drawings, this invention is illustrated as it isapplied to a :blindstitch sewing machine of the type having a frameincluding a base 11, a standard 12 rising from the base, a bracket arm13 extending laterally from the standard and a sewing head 14 projectingforwardly from the bracket arm.

Fixed Iwith respect to the sewing head 14 is a presser foot 15 againstthe under surface of which the fabric to be stitched is adapted to bear.The presser foot is formed in a conventional manner with an aperture(not shown) through which a ridge of fabric is adapted to be forcedupwardly and into the path of travel of a curved needle 16 carried inthe sewing head. Also carried in the sewing head is a looper 17cooperating with the needle in the formation of chain stitches, and awork feeding member 18 provided with a serrated work engaging lowersurface 19 adapted to extend downwardly through slots formed in thepresser foot 15 into engagement with the work fabrics.

The work fabrics are carried beneath the presser foot on a worksupporting table 21 which is pivotally supported in the usual manner ona pivot pin 22 carried in a bracket 23 secured on the front end of themachine base 11. The work supporting table 21 is also formed with afront skirt 24 to which a coil spring 25 is connected `by means of a pin26. The coil spring extends rearwardly into the machine bed and issecured to a stud bolt 27 fastened in the rear wall of the base 11 andby which the coil spring is tensioned so as to urge the work table in acounterclockwise direction about the pivot pin 22 and `thus to urge thework. supporting table toward the presser foot.

Carried beneath the work table 21 is a ridge forming mechanism indicatedgenerally as 28. The ridge former mechanism may be of any conventionaltype actuated by operable connections extending through the frame anddriven by drive shafts 29 and 30 in the bracket arm 13. This mechanismmay, for instance, be of the type disclosed in my U.S. Patent No.2,743,688, May 1, 1956, to which reference may `be had for a completedisclosure thereof. The ridge forming mechanism includes a ridge former31 which operates to` force a ridge of the work fabrics upwardly throughan aperture in the presser foot and into the path of the curved needle16. The extent to `which the ridge former forces the fabric upwardlythrough the presser foot 15 determines the depth or extent of needlepenetration of the fabrics. In the machine of the present invention theextent of ridge former effectiveness is determined by means of amechanism for limiting the proximity of the work supporting table 21 tothe presser foot 1S; thus the nearer the table 21 is permitted toapproach the presser foot, the more effective the `ridge former becomes.

Referring more particularly to Fig. l, movement of the work supportingtable 2.1 in a `counterclockwise direction and toward the presser foot15 is limited by a stop member in the form of a stop lever 32 which isfulcrumed upon the work table pivot pin 22 and is formed with a shortdepending stop arm 33 disposed to abut the front skirt 24E ofthe worktable. The stop lever 32 is formed with an arm 3ft which extendsrearwardly within the machine base and is slot-ted,` as at 35, at itsfree extremity to straddle a shoulderedpivotscrew icarriedby a threadedstud 37. The stud 37 forms a part of a control device which serves todetermine the position of the stop lever 32 and hence of the upper limitof work support movement. The stud 37 threadedly engages a controlmember `which takes the form of a rod 3S journaled for both turning andendwise sliding movements in the machine frame. The rod 38 is threaded,as at di), to accommodate the stud 37 and is formed between its endswith a plurality of annular serrations si shaped in the form of gearteeth to provide a rack lengthwise of the control member. Meshing withthe gear tooth-shaped serrations 41 is a gear segment i2 fast on thestud shaft 43 journaled in a bushing 44 secured to the fro-nt wall ofthe machine standard 12. The stud shaft d3 has secured thereto,exteriorly of the machine frame, a hand lever 45 which extends into thespace between the standard 12 of the machine frame and a plate 46 whichis supported in spaced relation to the standard by means of fasteningscrews 47--47 and a spacing block 4S. An arcuate slot 49 formed in theplate i6 accommodates a stud bolt Sil fixed in the hand lever d5 andthreadedly engaging a `clamp nut 51 by which the hand lever may beturned within the range of movement provided lby the arcuate slot 49. Bytightening the clamp nut 51, the hand lever may ybe locked with respectto the machine frame in any selected position along the arcuate slot 49.

When the hand lever i5 is turned, the gear segment 42 imparts endwisesliding movement to the rod 38 and with it to the stud 37 which by wayof its slidingly pivotal connection 35-36 with the stop lever arm 34effects a relatively large adjustment of the stop lever position. Thehand lever 4-5, therefore, provides a means for the machine operator toeifect rapid adjustment of the work table height to any selectedposition within the permissible range of adjustments. Such rapidadjustment is Patented July 21, 1959 advantageous, for instance, whenthe machine is called upon to sew a completely different weight orthickness of fabric.

There is also the need in this type of blindstitch machine for a meansto effect an exceedingly ne or micrometer adjustment of the work tableheight, as when adjusting the machine to sew, for instance, through onlyone of a plurality of plies of fabric. In the construction of thepresent invention such micrometer adjustment of work `table height maybe accomplished in any position of the hand lever 45 fby tightening theclamp nut 51 which acts to restrain the control member or rod 38 againstendwise movement in the frame, and then by turning the control rod bymeans of a hand wheel 52 secured to its free extremity. The threadedconnection between the control rod 38 and the threaded stud 37 provides,in effect, a turnbuckle, and since the control rod is restrained againstendwise movement, turning of the rod will effect a tine micrometeradjustment of the position of the stop member 32, and hence, of the Worktable height. Y

Having thus described the nature of the invention, what I claim hereinis:

1.r A work table height adjusting mechanism for a blindstitch sewingmachine having a frame, comprising a work table stop member shiftablysupported on said frame, a threaded stud operatively associated withsaid stop member, a control rod rotatably journaled in said frame, saidcontrol rod being threaded axially to accommodate said threaded stud,operator influenced means for turning said control rod, a series ofaxially spaced annular gear tootheshaped serrations formed on saidcontrol rod providing an annular rack thereon, a gear carried forturning movement in said frame and disposed in mesh with said annularrack, operator influenced gear turning mechanism carried by said frame,and means for clamping said gear turning mechanism rigidly to said framein any selected position of adjustment thereof.

2. A work table height adjusting mechanism for a blindstitch sewingmachine having a frame, comprising a Work table stop member shiftablysupported on said i frame, a threaded stud operatively associated withsaid stop member, a control rod rotatably journaled in said frame, saidcontrol rod being threaded axially to accommodate said threaded stud,operator inuenced means for turning said control rod, a series ofaxially spaced annular gear tooth-shaped serrations formed on saidcontrol rod providing an annular rack thereon, a shaft journaled in saidframe transversely of said control rod, a gear fast on said shaft withinsaid frame and disposed in mesh With said annular rack, an armconstituting a handle fast on said shaft exteriorly of said frame, andclamp means effective to secure said handle in any selected positionwith respect to said frame.

3. A work table height adjusting mechanism for a blindstitch sewingmachine having a frame, comprising a work table stop member shiftablysupported on said frame, a threaded stud operatively associated withsaid stop member, a control rod rotatably journaled in said frame, saidcontrol rod being threaded axially to accommodate said threadedvstud,operator influenced means for turning said control rod, a series ofaxially spaced annular gear tooth-shaped serrations formed on saidcontrol rod providing an annular rack thereon, a shaft journaled in saidframe transversely of said control rod, a Kgear fast on said shaftwithin said frame and disposed inmesh with said annular rack, an armconstituting a handle fast on said shaft exteriorly of said frame, aplate projecting from said frame and associated rigidly therewith, saidplate being formed with an arcuate slot having its center of curvaturecoincident With the axis of said shaft, a threaded pin carried by saidhandle and disposed to extend through said arcuate slot, and a clamp nutcarried on said threaded pin at the side of said plate opposite saidhandle.

References Cited in the le of this patent UNITED STATES PATENTS 745,736Onderdonk Dec. 1, 1903 1,689,846 Woodcock Oct. 30, 1928 2,514,837 BuonoJuly 11, 1950

